This invention is concerned with improvements in or relating to wheelchairs. In particular, this invention is concerned with electric driving means suitable for a wheelchair, as well as a wheelchair embodying electric driving means.
It is already known to use electric driving means for wheelchairs, but the known constructions have certain disadvantages some of which lead to the wheelchair being unacceptable to the user or to disapproval by controlling or regulating authorities in certain countries. For example, a belt drive to the wheels from an electric motor is generally regarded as dangerous and unsatisfactory; a direct drive from an electric motor to one or two wheels is unsatisfactory unless the drive includes a clutch because on power failure the manual propulsion power to advance the wheelchair also has to rotate the motor, additionally on mechanical failure even with a clutch, manual propulsion may not be possible. The electric motor with a direct drive may not have a power output range sufficient to meet the range of speeds and loading encountered in the everyday use of a wheelchair such as from indoors with very low speeds on substantially flat floors to road use at higher speeds say 4 miles per hour on gradients of up to 1 in 4.